The parties' two MEPs clashed over Brexit and its implications for the Irish border, international trade and farm subsidies on the BBC's Talkback programme.

Mrs Dodds said: "This is a good day for democracy; a good day for the principles of free and fair government; a good day for us to restore the sovereignty of our national law-making in Westminster and in the devolved settlements in Northern Ireland, Scotland and Wales."

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A letter signed by Prime Minister Theresa May was hand delivered to EU Council President Donald Tusk

The DUP MEP added that everyone needed to realise that "Brexit is a reality".

She called on those who campaigned for and against leaving the EU to set aside "divisive rhetoric" and work together to get the best deal for Northern Ireland.

However, her Sinn Féin counterpart said: "This is a disaster, an absolute fiasco."

Ms Anderson added: "What was are dealing with is the potential reinforcement of partition, I think the DUP knew that and that's why they advocated to leave."

She accused the DUP of "arrogance" over the uncertainty facing farmers, who currently receive a "substantive amount of funding" from the EU.

"And anyone that's being fooled by the notion that the British government is going to replace the Single Farm Payment... there is not a hope in hell, in my opinion, that a hostile, hawkish British government - a Tory administration - is going to replace that.

"I feel sorry for those farmers who believed the DUP's spin."

No regrets

But Mrs Dodds said the Westminster government had confirmed that it would "continue to support farming".

She said that, under a commitment made by Chancellor Philip Hammond, "any funding from Europe that already is there - in terms of farming, in terms of direct support - up until 2020 is still there".

"That's as far as we can go in terms of the European Union," Mrs Dodds added.

Asked if she regretted her choice of phrase, Ms Anderson told Talkback she had been expressing the "mood and the views" of border communities.

"I stand over the language that I used," the Sinn Féin MEP said.

"It may not have been the language that other people would have used, but it was reflective of the deep, genuine feelings and fears that I am meeting on a daily basis."

Image copyrightPress EyeImage caption
Brexit protesters held a demonstration at Stormont on the day Article 50 was triggered

However, Mrs Dodds said Brexit negotiations could deliver a "seamless border" between Northern Ireland and the Republic of Ireland.

"There is no reason why we cannot employ technology, why we cannot employ goodwill - and remember it is in the interests of the Republic of Ireland, as much as it is in the interests of the rest of the United Kingdom to make sure that the border is as seamless as we can possibly make it."

The DUP MEP added: "Already, as part of our opt out from the Schengen Agreement - which is the borderless travel area for the rest of Europe - the European Union allows some extra external controls at the outside borders of the United Kingdom and the Republic of Ireland.

" I don't think it's a step to far to actually make that a reality, post-Brexit."

You can watch a special TV programme on Article 50 on BBC One Northern Ireland on Wednesday 29 March at 19:00 GMT. "Brexit - What Next" is hosted by Andrew Neil and Tara Mills.